1. Field of the Invention
The invention relates to a rib for a firearm, especially a shotgun, and a method for making a barrel provided with a rib.
To focus on a target with a firearm, for example a shotgun (smoothbore rifles), a rib is mounted on the top of the barrel and used for sighting when shooting. This rib extends over at least a portion of the barrel and is permanently or adjustably connected to the barrel.
2. Description of the Related Art
Known shotgun ribs are milled from metal and soldered or brazed to the barrel. During manufacture, the barrel and the rib are white-finished, then soldered together and finally black-finished or black-finished. Milling the ribs is highly labor-intensive and the soldering to the barrel is difficult.
To simplify the manufacture of a revolver barrel with a rib, the rib can be made from die-cast zinc and fastened to the muzzle of the barrel or the frame of the revolver. However this is not possible in a shotgun, because a rib of this kind fastened only at its ends is not sufficiently rigid. Additionally bolting the rib between its ends to the barrel is not possible because of the generally thin wall of the barrel.
In most instances, ribs are mounted on single-barrel shotguns (top-break shotguns, repeating shotguns, automatic shotguns, or double-barreled shotguns). It is also possible however to use ribs in conjunction with weapons in which two, and theoretically even more, barrels are located one above the other or side by side, such as double-barreled shotguns, over-and-under shotguns, and double-barreled rifles. On single-barreled rifles as well (such as top-break or repeating rifles, a rib is often provided. The rib can have a flat surface or a surface that is bent downward (so-called hollow ribs). The cross section of a rib can be limited on the top by a straight line (with respect to the line of sight) or can be curved so that the rib forms a shallow groove to some degree.
When several shots are to be fired sequentially from a shotgun barrel, as is often the case when hunting or skeet shooting, the barrel heats up considerably. Consequently the air in the vicinity of the barrel is heated as well. As a result the shooter does not see a clear image as he looks along the line of sight, but a more or less seriously distorted image, called schlieren or schliering (optical inhomogeneities in the air caused by heat). This defect is reinforced by conventional welded ribs since these form a sort of cooling rib on the barrel, where an especially intensive heat exchange with the ambient air takes place. In order to reduce the schliering in the vicinity of the line of sight, particularly in sporting shotguns, so-called ventilated ribs are used that have openings in the side abutting the barrel. These openings can be traversed by cooling air and thus constitute ventilated spaces between parts of the rib and the top of the barrel facing it. These spaces are separated from one another by sections of the rib in the shape of bridge piers that extend to the barrel and are welded to it. No ventilation takes place in the vicinity of these openings, so that schlieren waves still occur at least these areas.
Ventilated ribs also have the advantage that they are lighter than solid ribs. Consequently, not only is the total weight of the shotgun reduced, but tracking a moving target with the shotgun is facilitated as well. One disadvantage of the ventilated rib is its increased manufacturing cost, since the openings must be milled cleanly. The object of the present invention is to provide an improved rib and consequently an improved barrel. The rib is intended to be simple to manufacture and mountable on the barrel.